In 1519, Cortés entered Tenochtitlán, the capital of the Aztec/Mexica Empire. ... In August 1521, Cortés claimed Tenochtitlán for Spain and renamed it Mexico City.
The Spanish place the capital of colonial Mexico where they did due to a domination strategy. During the final stage of the Spanish conquest of the Aztecs, Tenochtitlan was besieged and essentially razed. Hernán Cortés understood the strategic and symbolic importance of the Aztec capital and founded the Spanish capital of Mexico City on the site, and in particular rebuilt the Aztec ceremonial and political center as the main square, the Plaza Mayor, usually called the Zócalo.
After landing near the modern-day city of Veracruz, Hernán Cortés heard about the great city and also learned of long-standing rivalries and grievances against it. Although Cortés came to Mexico with a very small contingent of Spaniards, he was able to persuade many of the other Indian peoples to help him destroy Tenochtitlan.
For a time, these allied peoples made use of the arrival of the European in the hopes of creating a world freed of Aztec domination. Spanish objective, however, was that they themselves would benefit from the destruction of Tenochtitlan, making the Indians not free, but rather more subservient to the Spaniards than they were to the Aztecs
